Quando ho iniziato la mia work as a designer I ran into a problem, I tried to make public a letter sent to the official magazine dell'AEIT. At a distance of decades, the problem remains open.
It is important switchboards equipped with circuit breakers with breaking just over the value of the short circuit current that can affect them (eg 60 kA and 55 kA respectively). Often downstream processors of high average power-type low-loss power factor of the short-circuit current is lower than those associated with the breaking by the manufacturer in accordance with the relevant technical standards (eg 0.18 against 0.2 Association for breaking more than or equal to 50 kA).
In this regard we have to lead us as designers and consultants.
E 'possible to get an answer after decades?
What might be the state of the art on the subject. We
designers and verifiers should encourage regulators as manufacturers switch to provide rules / equipment better suited to actual plant requirements, particularly if they involved issues that relate to security and even if it can be very expensive.
In the past I have repeatedly expressed my thoughts on the article that appeared in some magazines. Never received responses. I raised the issue with the magazine Tuttonormel, which, in my opinion, the skills to speak authoritatively.
very timely response of prof. Carrescia Vito, director of the magazine and certainly one of the leading experts in electrical safety, and I thank him, he confirmed my thought: manufacturers must indicate how the various breaking of protective equipment to reduce the power factor compared to the nominal one.
